Less than 60% of total points or less than 50% of exam points
indicates a failing grade.

Q 1.9 refers to one of the 'Questions' at the back of the
chapter.
EP 1.7 refers to one of the 'Exercises'
or 'Problems' at the back of the chapterTU 2.2 refers to a 'Test Your Understanding'
question on section 2.2 embedded in Chapter 2
(There are answers at the end of each chapter on the TU quesions)